and elsewhere have resurfaced questions about what can be done to prevent these terrible events.Nineteen states-as politically diverse as Florida and California-have laws on the books to temporarily prohibit gun purchase and possession by people who are behaving dangerously and at risk of committing violence, including self-harm. However, early evidence indicates that few clinicians are aware of how to use this emerging legal tool to prevent violence.Here are the basics. In each state that has authorized what are called extreme risk protection orders (ERPOs), the law sets out who can file a petition with a civil court about someone of concern.Eligible petitioners always include law enforcement officers; in most states, family members are eligible, and in Hawaii, Maryland, and Washington, DC, clinicians are on the list. The petitions specify the reasons for concern, such as threatening violence, illegally and recklessly brandishing a gun, or articulating a suicide plan. A judge then reviews the request and decides whether to issue an ERPO. In most cases, the petitions are granted, leading to temporary removal of firearms for up to 1 year. After